The suicide of an 18-year-old Rutgers University student following an unimaginable invasion of his privacy has launched an overdue examination of casual — and possibly criminal — disregard for others’ personal space.

Freshman Tyler Clementi walked onto the George Washington Bridge the night of Sept. 22 and jumped over the edge. A few days earlier, authorities say, his roommate, Dharun Ravi, and a friend, Molly Wei, had placed a webcam in the dorm room Clementi and Ravi shared, filmed Clementi in an intimate encounter with another man, and posted it online for all to see.

There are several dimensions to the story, complicated by the fact that the victim was gay. Based on Internet postings, it appears that Ravi targeted his roommate because of his sexual orientation.

Was it a hate crime, or simply a stupid prank that once would have been inconceivable? It was surely an act of unforgivable bullying. Should the alleged perpetrators be prosecuted for invasion of privacy, for which they have been charged, and/or a hate crime?

Answers to those questions will have to await investigators. For now, other questions also beg our attention. How did we get here? How could anyone think that another’s most private, intimate moment was fair game? Although Clementi was filmed with another man, one can imagine as easily a roommate spying on a heterosexual encounter.

The emergence of social media, combined with mass access to technology — camera-equipped cellphones, pocket-sized video cameras and blogospheric distribution — has enabled an insatiable market for spying and gossip. The result has been a cultural breakdown in decency and a blurring of the boundaries of what should be private and public.

Even this discussion feels like an invasion of privacy, given the unbearable pain the Clementi family must be enduring. But sometimes it takes a tragedy to shake us from complacency. Just as Matthew Shepard’s brutal murder in Wyoming in 1998 awakened Americans to the suffering of gays — a mobilized outrage — maybe Tyler Clementi will help us recognize how ugly we have become in our worship of this voyeuristic, celebrity culture.

There is welcome movement from groups and individuals (notably Ellen DeGeneres) toward letting young gays and lesbians know where they can find support. Bravo.

To that necessary objective, we should add an urgent call to renew respect for privacy. As a community of decent people, we have to rally ourselves to stop the insanity of narcissism and exhibitionism that inculcates the broader notion that nothing is off-limits.

Especially poignant was Clementi’s final note to the world, a Facebook status update saying that he was going to kill himself — an electronic adieu to his “friends,” those random and often anonymous folks who sign up to follow one’s life online.

Friend, the noun, has become meaningless in a world where “friending” is a verb. And privacy, I keep hearing, is dead forever. I don’t buy it.

There was once a time when respecting others’ privacy was a matter of manners. Of course, it was also considered bad manners to display oneself — or one’s affections — in public. Some call it puritanism. I call it civilization.

We don’t want to outlaw cameras or otherwise limit free expression, but we can certainly make it unattractive and unacceptable to intrude on others. Next time someone takes your picture or posts it on the Internet without your permission, raise the roof. Point a finger. Stand athwart civilization and yell, no more.

When others are victimized by another’s lack of scruples, be outraged. And never, ever point a camera at anyone without his or her permission.